A firmware download method has been proposed for downloading firmware program data from a host device to a card reader (Patent reference 1, for example).
According to the download method disclosed in Patent reference 1, a download file including the program data is stored in a host device; when the revision information of the download file saved in the host device doesn't match a response from the card reader to a get-revision-information command issued by the host device, the program data is downloaded from the host device to the card reader.